CVE-2025-49587 is a medium-severity vulnerability affecting the XWiki platform, an open-source wiki software widely used for collaborative documentation and knowledge management. The vulnerability arises due to insufficient user interface warnings when handling potentially dangerous operations involving the XWiki.Notifications.Code.NotificationDisplayerClass object. Specifically, if a user without script rights creates a document containing this object, and subsequently an administrator edits and saves that document, the content of the object can be rendered as raw HTML. This behavior enables cross-site scripting (XSS) attacks, as malicious HTML or script code embedded in the object can execute in the context of the administrator's browser. The vulnerability is tied to the way Velocity templates are executed within the notification displayer, but prior to version 15.9, there were no warnings to alert administrators about the risks of editing documents containing such potentially dangerous properties. Starting with XWiki 15.9, generic analyzers began warning admins before editing Velocity code, but warnings specifically for dangerous properties were only introduced in later versions. The issue has been addressed in patched releases 15.10.16, 16.4.7, and 16.10.2 by implementing a required rights analyzer that proactively warns administrators before editing documents that may contain malicious code. The affected versions span from 15.9-rc-1 up to but not including these patched versions. The CVSS 4.0 score of 6.4 reflects a medium severity, considering the network attack vector, low attack complexity, no privileges required for the initial malicious document creation, but requiring administrator interaction (UI) to trigger the exploit. No known exploits are currently reported in the wild. This vulnerability primarily impacts the confidentiality and integrity of administrative sessions by enabling XSS attacks, which could lead to session hijacking or unauthorized actions performed with admin privileges within the XWiki platform.

For European organizations utilizing XWiki as part of their internal knowledge management or collaborative platforms, this vulnerability poses a significant risk to administrative accounts and sensitive information. Successful exploitation could allow attackers to execute arbitrary scripts in the context of an administrator's browser, potentially leading to session hijacking, privilege escalation, or unauthorized modification of wiki content. This can compromise the integrity and confidentiality of organizational data, disrupt collaboration workflows, and damage trust in internal systems. Given that many European public sector entities, educational institutions, and enterprises rely on open-source platforms like XWiki, the risk is amplified where administrative users have elevated privileges and access to sensitive documentation. Additionally, the vulnerability could be leveraged as a foothold for further lateral movement within the network if attackers gain admin-level access. The requirement for user interaction (admin editing the malicious document) limits automated exploitation but does not eliminate risk, especially in environments with multiple administrators or less stringent operational controls. The high scope impact (SI:H) indicates that successful exploitation affects resources beyond the initially vulnerable component, potentially impacting the entire platform's security posture.

To mitigate this vulnerability effectively, European organizations should: 1) Immediately upgrade all affected XWiki instances to the patched versions 15.10.16, 16.4.7, or 16.10.2, depending on their current deployment branch. 2) Implement strict role-based access controls to limit document creation and editing permissions, especially restricting who can create documents with script-related objects. 3) Enforce multi-factor authentication (MFA) for all administrative accounts to reduce the risk of session hijacking. 4) Conduct regular audits of documents containing the XWiki.Notifications.Code.NotificationDisplayerClass object or other potentially dangerous properties to identify and remediate suspicious content. 5) Train administrators to recognize and heed UI warnings introduced in patched versions, emphasizing caution when editing documents flagged as potentially dangerous. 6) Utilize web application firewalls (WAFs) with custom rules to detect and block suspicious HTML or script payloads in wiki content submissions. 7) Monitor administrative activity logs for unusual editing patterns or access from unexpected IP addresses. 8) Where possible, isolate the XWiki platform within segmented network zones to limit lateral movement in case of compromise. These targeted measures go beyond generic patching advice by focusing on operational controls, user training, and proactive monitoring tailored to the nature of this vulnerability.